Treatment of liquid hydrocarbon products



Patented Sept. 3, 1940 UNITED STATES TREATBIENT OF LIQUID HYDROCARBON PRODUCTS Henry Dreyfus, London, England No Drawing. Application January 29, 1938, Se-

rial No. 187,661. 1937 2 Claims.

This invention relates to the treatment of liquid hydrocarbon products and in particular to the treatment of tar oils and other liquid products obtained from coal.

In the distillation of coal both by low temperature and high temperature processes the tar oils obtained contain quantities of oxygen-containing compounds mainly of phenolic character. The present invention is concerned broadly with the treatment of these tar oils and otherliquid products obtained from coal, for instance the products obtained by extraction of coal with organic solvents, with the object of forming products consisting substantially of hydrocarbons.

According to the invention liquid coal products are subjected to treatment with metals or metal compounds, and in particular with oxides or hydroxides of alkaline earth metals or alkali metals. The treatment of such liquid coal products with an oxide or hydroxide of an alkaline earth metal or of an alkali metal results in the production of salts by reaction between the oxide or hydroxide and phenolic compounds contained in the material treated, and decomposition of these salts produces hydrocarbons, the alkali metal or alkaline earth metal being recovered usually in the form of a carbonate. In this manner oxygencontaining compounds contained in the liquid coal product treated are transformed into hydrocarbons without the utilisation of hydrogen or any other reducing gas. Furthermore, sulphur contained in the liquid coal product combines with the alkali metal or alkaline earth metal and may be removed from the liquid coal product by separation of the salts formed.

Formation of the salt can be efiected at room temperatures but, if desired, higher temperatures may be employed to accelerate the reaction, e. g. temperatures of 50-100 C. or more. Decomposition of the salt formed is preferably effected at as low a temperature as is possible in order to avoid decomposition or polymerisation of the hydrocarbons formed. In practice it is convenient to efiect the decomposition during a distillation operation, for instance when fractionating the liquid coal product.

The salt produced by treating the liquid coal product with the alkali metal or alkaline earth metal oxide or hydroxide may, if desired, be separated from the liquid coal product before being decomposed. On the other hand the decomposition may be effected in the liquid coal product itself and thus the process of the invention may consist of mixing the liquid coal product with the oxide or hydroxide chosen, e. g. lime or caustic soda, and subjecting the resulting mixture to a sufficiently high temperature to produce hydrocarbons from oxygen-containing compounds present. There may also be used instead of alkali metal or alkaline earth metal oxides or In Great Britain February 3,

hydroxides, metals such as zinc and copper which when heated with the liquid coal products cause decomposition of oxygen containing organic compounds present with the formation of hydrocarbons. Metal oxides formed as a result of such an operation may be regenerated by reduction, particularly with a reducing gas which is cheaper than hydrogen; this may be, for instance, carbon monoxide, water gas or methane according to the processes being operated. Alternatively, the metal oxide may be reduced by heating with carbon. 1

The following examples illustrate the process of the invention:

Example 1 Tar oil produced by the low temperature distillation of coal is mixed with lime in the proportion of 5 to 6 parts by weight of lime per 100 parts of tar oil. The mixture is heated to a temperature of 70-75 C. and maintained at this temperature for an hour, during which the mixture is maintained in agitation.

The tar oil is then subjected to fractional distillation to separate it into high and low boiling fractions and during the later stages of distillation the calcium salts present in the tar oil are decomposed to produce hydrocarbons which distil over.

Erwmple 2 Tar oil produced by the low temperature distillation of coal is mixed with finely powdered metallic zinc in the proportion of 3 to 4 parts by Weight of zinc per 100 parts of tar oil and the mixture is immediately subjected to fractional distillation. During the distillation process the metallic zinc reacts with oxygen-containing compounds contained in the tar oil forming metal compounds which decompose subsequently to produce hydrocarbons.

The semi-solid residue from the fractional distillation is burnt to remove carbonaceous matter and the zinc oxide thus obtained is reduced by treatment with water-gas.

Having described my invention, what I desire to secure by Letters Patent is:

1. Process for the treatment of crude liquid coal products, which comprises transforming phenolic compounds contained therein into liquid hydrocarbons Without utilization of hydrogen by heating the crude liquid coal products with a finely divided metallic zinc.

2. Process for the treatment of crude liquid coal products, which comprises transforming phenolic compounds contained therein into liquid hydrocarbons without utilization of hydrogen by subjecting the crude liquid coal products to distillation in the presence of finely divided metallic zinc.

HENRY DREYFUS. 

